Biodegradable polylactic acid resin compositions and the like are proposed as packaging materials (see Patent Documents 1 and 2). However, a packaging container using such a biodegradable resin composition is sequentially degraded from the surface of the container. Thus, complete degradation of the whole container takes a considerable time. In addition, there is a problem that such a biodegradable container has readily degradable portions and hardly degradable portions, since the degradation rate is influenced by the internal structure of the resin such as the crystallinity of the resin and the molecular orientation thereof.
Patent Document 1: Japanese Patent Application Publication No. Hei 11-116788
Patent Document 2: Japanese Patent Application Publication No. Hei 9-316181